10 research outputs found
An alternative approach to efficient simulation of micro/nanoscale phonon transport
Starting from the recently proposed energy-based deviational formulation for
solving the Boltzmann equation [J.-P. Peraud and N. G. Hadjiconstantinou, Phys.
Rev. B 84, 2011], which provides significant computational speedup compared to
standard Monte Carlo methods for small deviations from equilibrium, we show
that additional computational benefits are possible in the limit that the
governing equation can be linearized. The proposed method exploits the
observation that under linearized conditions (small temperature differences)
the trajectories of individual deviational particles can be decoupled and thus
simulated independently; this leads to a particularly simple and efficient
algorithm for simulating steady and transient problems in arbitrary
three-dimensional geometries, without introducing any additional approximation.Comment: 4 pages, 2 figure
Disparate quasiballistic heat conduction regimes from periodic heat sources on a substrate
We report disparate quasiballistic heat conduction trends for periodic nanoscale line heaters deposited on a substrate, depending upon whether measurements are based on the peak temperature of the heaters or the temperature difference between the peak and the valley of two neighboring heaters. The degree of quasiballistic transport is characterized by the effective thermal conductivities of the substrate which are obtained by matching the diffusion solutions to the phonon Boltzmann transport equation results. We find that while the ballistic heat conduction effect based on the peak temperature diminishes as the two heaters become closer, it becomes stronger based on the peak-valley temperature difference. Our results also show that the collective behavior of closely spaced heaters can counteract the nonlocal effects caused by an isolated nanoscale hot spot. These results are relevant to thermal conductivity spectroscopy techniques under development and also have important implications for understanding nonlocal heat conduction in integrated circuits and carbon nanotube array thermal interface materials.United States. Dept. of Energy. Office of Science (Award DE-SC0001299/DE-FG02-09ER46577